It’s commonplace in my field (nuclear physics) to share the preprint version of your article, typically on arxiv.org. You can update the article as you respond to peer reviewers too. The only difference between this and the paywalls publisher version is that version will have additional formatting edits by the journal.
If you search for articles on google scholar, it groups the preprint and published versions together so it’s easy to find the non-paywalled copy. The standard journals I publish in even sort of encourage this; you can submit the latex documents and figures by just putting the url to an arxiv manuscript.
The US Department of Energy now requires any research they fund be made publicly available. So any article I publish is also automatically posted to osti.gov 1 year after its initial publication. This version is also grouped into the google scholar search results.
It’s an imperfect system, but it’s getting much better than it was even just a decade ago.